Conventional circuit devices which are highly integrated (e.g., semiconductors) typically contain fine patterns. In order to fabricate such devices, it is highly desirable to develop new lithography processes. For example, new resist materials which can react to light emitted from an ArF excimer laser having wavelengths of about 193 nm may be utilized.
In conventional semiconductor device manufacturing processes, single layer resists (SLRs) or bi-layer resists (BLRS) are typically utilized. An SLR is usually less sophisticated than a BLR. However, when an SLR is used in forming a resist pattern, it may be difficult to ensure a sufficient dry etch resistance. Moreover, a resist pattern formed from an SLR may become slanted and collapse in the event the aspect ratio increases.
A conventional BLR usually contains silicon. With respect to a BLR, a process for forming a resist pattern may be more complicated relative to a process using an SLR. Nonetheless, a process involving a BLR may be more advantageous than a process which utilizes an SLR. In particular, silicon atoms of the resist material are typically converted to glass during an O.sub.2 plasma dry etching process. As a result, a cured layer may be formed on the surface of the resist layer. The cured layer can serve as an etching mask during a subsequent dry etching process. Thus, a resist pattern having a high aspect ratio may be readily formed.
When manufacturing a BLR, the silicon content of a polymer which is employed may play a significant role. A silicon-containing polymer intended to be used as a BLR for an ArF excimer laser lithography process is proposed by Kotachi, A., "Si-Containing Positive Resist for ArF Excimer Laser Lithography", Journal of Photopolymer Science and Technology, 8:4, p. 615 (1995). The silicon content of the polymer is taught to be around 8 weight percent. Considering that it may be more preferable to have employ a polymer having a silicon content of at least 10 weight percent, it may be difficult to obtain a sufficiently high aspect ratio utilizing the polymer proposed by Kotachi et al. Additionally, the polymer proposed in Kotachi et al. may display inferior adhesive properties. As a result, a resist layer which contains the polymer may detach from an underlying layer in a device comprising the resist layer.
There remains a need in the art to address the potential difficulties associated with conventional polymeric materials used in resist layers.